public double MinimumLength {get; set;}

// must be on MCT 

var pipelineFilter = new LasPointPipelineSelectionFilter();
        
pipelineFilter.VisiblePoints = true;
pipelineFilter.ClassCodes = new List<int>();  // empty list means all classification codes
pipelineFilter.FilterGeometry = geometry;

// configure a few of the properties and accept defaults for others
pipelineFilter.ApplyWindCorrection = true;
pipelineFilter.MinimumLength = 25;  // meters

var pipelineSelCount = await lasDatasetLayer.SelectAsync(pipelineFilter, SelectionCombinationMethod.New);